Nitrofuran Antibacterial

Nitrofurantoin

Approved 11 May 2011OralSuspension

The FDA lists this product in 22 strengths and forms.

Indications

Nitrofurantoin oral suspension is specifically indicated for the treatment of urinary tract infections when due to susceptible strains of Escherichia coli, enterococci , Staphylococcus aureus , and certain susceptible strains of Klebsiella and Enterobacter species. Nitrofurantoin oral suspension is not indicated for the treatment of pyelonephritis or perinephric abscesses. Nitrofurantoins lack the broader tissue distribution of other therapeutic agents approved for urinary tract infections.

Consequently, many patients who are treated with nitrofurantoin oral suspension are predisposed to persistence or reappearance of bacteriuria. Urine specimens for culture and susceptibility testing should be obtained before and after completion of therapy. If persistence or reappearance of bacteriuria occurs after treatment with nitrofurantoin oral suspension, other therapeutic agents with broader tissue distribution should be selected.

In considering the use of nitrofurantoin oral suspension, lower eradication rates should be balanced against the increased potential for systemic toxicity and for the development of antimicrobial resistance when agents with broader tissue distribution are utilized.

Contraindications

Anuria, oliguria, or significant impairment of renal function (creatinine clearance under 60 mL per minute or clinically significant elevated serum creatinine) are contraindications. Treatment of this type of patient carries an increased risk of toxicity because of impaired excretion of the drug. Because of the possibility of hemolytic anemia due to immature erythrocyte enzyme systems (glutathione instability), the drug is contraindicated in pregnant patients at term (38 to 42 weeks gestation), during labor and delivery, or when the onset of labor is imminent.

For the same reason, the drug is contraindicated in neonates under one month of age. Nitrofurantoin oral suspension is contraindicated in patients with a previous history of cholestatic jaundice/hepatic dysfunction associated with nitrofurantoin. Nitrofurantoin oral suspension is also contraindicated in those patients with known hypersensitivity to nitrofurantoin.

Warnings and precautions

Pulmonary reactions ACUTE, SUBACUTE, OR CHRONIC PULMONARY REACTIONS HAVE BEEN OBSERVED IN PATIENTS TREATED WITH NITROFURANTOIN. IF THESE REACTIONS OCCUR, NITROFURANTOIN ORAL SUSPENSION SHOULD BE DISCONTINUED AND APPROPRIATE MEASURES TAKEN. REPORTS HAVE CITED PULMONARY REACTIONS AS A CONTRIBUTING CAUSE OF DEATH. CHRONIC PULMONARY REACTIONS (DIFFUSE INTERSTITIAL PNEUMONITIS OR PULMONARY FIBROSIS, OR BOTH) CAN DEVELOP INSIDIOUSLY.

At a glance

Brand name: Nitrofurantoin
Pharmacologic class: Nitrofuran Antibacterial
Route: Oral
Dosage form: Suspension
Applicant: Amneal Pharms
Status: Discontinued
FDA approval: 11 May 2011
Application: ANDA201679-001

Indications

Contraindications

Warnings and precautions

Pregnancy and breastfeeding

8.1Pregnancy Risk Summary

Nitrofurantoin is contraindicated in pregnant women at term (38 weeks to 42 weeks gestation), during labor and delivery, or when the onset of labor is imminent because of the possibility of hemolytic anemia in the infant (see Clinical Considerations ) . Published epidemiological studies, including cohort studies and case control studies, have reported inconsistent findings related to nitrofurantoin use during the first trimester and risk of major birth defects.

These studies cannot definitively establish the presence or absence of risk due to several methodological limitations. The limited number of epidemiological studies available have not identified drug-associated risks of major birth defects, miscarriage or other adverse maternal or fetal outcomes. In animal reproduction studies, no fetotoxicity was observed when nitrofurantoin was administered orally to pregnant rats and rabbits, during organogenesis, at up to 6 times the recommended human dose (see Data ) .

The background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively. Clinical Considerations Fetal/Neonatal Adverse Reactions Nitrofurantoin is not recommended in pregnant women at term (38 weeks to 42 weeks gestation), during labor and delivery, or when the onset of labor is imminent because of the possibility of hemolytic anemia due to immature erythrocyte enzyme systems (glutathione instability) [see Contraindications (4) and Warnings and Precautions (5.4) ] .

Data Animal Data Several reproduction studies have been performed in rabbits and rats at doses up to six times the human dose and have revealed no harm to the fetus due to nitrofurantoin. In a single published study conducted in mice at 68 times the human dose (based on mg/kg administered to the dam), growth retardation and a low incidence of minor and common malformations were observed. However, at 25 times the human dose, fetal malformations were not observed.

Nitrofurantoin has been shown in one published transplacental carcinogenicity study to induce lung papillary adenomas in the F1 generation mice at doses 19 times the human dose on a mg/kg basis. The relationship of this finding to potential human carcinogenesis is presently unknown.

Adverse reactions

Respiratory CHRONIC, SUBACUTE, OR ACUTE PULMONARY HYPERSENSITIVITY REACTIONS MAY OCCUR. CHRONIC PULMONARY REACTIONS MAY OCCUR GENERALLY IN PATIENTS WHO HAVE RECEIVED CONTINUOUS TREATMENT FOR SIX MONTHS OR LONGER. MALAISE, DYSPNEA ON EXERTION, COUGH, AND ALTERED PULMONARY FUNCTION ARE COMMON MANIFESTATIONS WHICH CAN OCCUR INSIDIOUSLY. RADIOLOGIC AND HISTOLOGIC FINDINGS OF DIFFUSE INTERSTITIAL PNEUMONITIS OR FIBROSIS, OR BOTH, ARE ALSO COMMON MANIFESTATIONS OF THE CHRONIC PULMONARY REACTION.

FEVER IS RARELY PROMINENT. THE SEVERITY OF CHRONIC PULMONARY REACTIONS AND THEIR DEGREES OF RESOLUTION APPEAR TO BE RELATED TO THE DURATION OF THERAPY AFTER THE FIRST CLINICAL SIGNS APPEAR. PULMONARY FUNCTION MAY BE IMPAIRED PERMANENTLY, EVEN AFTER CESSATION OF THERAPY. THE RISK IS GREATER WHEN CHRONIC PULMONARY REACTIONS ARE NOT RECOGNIZED EARLY. In subacute pulmonary reactions, fever and eosinophilia occur less often than in the acute form.

Upon cessation of therapy, recovery may require several months. If the symptoms are not recognized as being drug-related and nitrofurantoin therapy is not stopped, the symptoms may become more severe. Acute pulmonary reactions are commonly manifested by fever, chills, cough, chest pain, dyspnea, pulmonary infiltration with consolidation of pleural effusion on x-ray, and eosinophilia. Acute reactions usually occur within the first week of treatment and are reversible with cessation of therapy.

Resolution often is dramatic (see WARNINGS ). Changes in EKG (e.g., non-specific ST/T wave changes, bundle branch block) have been reported in association with pulmonary reactions. Cyanosis has been reported rarely. Hepatic Hepatic reactions, including hepatitis, cholestatic jaundice, chronic active hepatitis, and hepatic neurosis, occur rarely (see WARNINGS ). Neurologic Peripheral neuropathy, which may become severe or irreversible, has occurred.

Fatalities have been reported. Conditions such as renal impairment (creatinine clearance under 60 mL per minute or clinically significant elevated serum creatinine), anemia, diabetes mellitus, electrolyte imbalance, vitamin B deficiency, and debilitating diseases may increase the possibility of peripheral neuropathy (see WARNINGS ). Asthenia, vertigo, nystagmus, dizziness, headache, and drowsiness have also been reported with the use of nitrofurantoin.

Benign intracranial hypertension (pseudotumor cerebri), confusion, depression, optic neuritis, and psychotic reactions have been reported rarely. Bulging fontanels, as a sign of benign intracranial hypertension in infants, have been reported rarely. Dermatologic Exfoliative dermatitis and erythema multiforme (including Stevens-Johnson syndrome) have been reported rarely. Transient alopecia also has been reported. Allergic A lupus-like syndrome associated with pulmonary reactions to nitrofurantoin has been reported.

Also, angioedema; maculopapular, erythematous, or eczematous eruptions; pruritus; urticaria; anaphylaxis; arthralgia; myalgia; drug fever; and vasculitis (sometimes associated with pulmonary reactions) have been reported. Hypersensitivity reactions present the most frequent spontaneously-reported adverse events in world-wide postmarketing experience with nitrofurantoin formulations. Gastrointestinal Nausea, emesis, and anorexia occur most often.

Abdominal pain and diarrhea are less common gastrointestinal reactions. These dose-related reactions can be minimized by reduction of dosage. Sialadenitis and pancreatitis have been reported. There have been sporadic reports of pseudomembranous colitis with the use of nitrofurantoin. The onset of pseudomembranous colitis symptoms may occur during or after antimicrobial treatment (see WARNINGS ). Hematologic Cyanosis secondary to methemoglobinemia has been reported rarely.

Miscellaneous As with other antimicrobial agents, superinfections caused by resistant organisms, e.g., Pseudomonas species or Candida species, can occur. There are sporadic reports of Clostridium difficile superinfections, or pseudomembranous colitis, with the use of nitrofurantoin. Laboratory Adverse Events The following laboratory adverse events have been reported with the use of nitrofurantoin; increased AST (SGOT), increased ALT (SGPT), decreased hemoglobin, increased serum phosphorus, eosinophilia, glucose-6-phosphate dehydrogenase deficiency anemia (see WARNINGS ), agranulocytosis, leukopenia, granulocytopenia, hemolytic anemia, thrombocytopenia, megaloblastic anemia.

In most cases, these hematologic abnormalities resolved following cessation of therapy. Aplastic anemia has been reported rarely. To report SUSPECTED ADVERSE REACTIONS, contact Amneal Pharmaceuticals at 1-877-835-5472 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.

Nitrofurantoin

Indications

Contraindications

Warnings and precautions

At a glance

Two medicines in one question?

Nitrofurantoin

Indications

Contraindications

Warnings and precautions

At a glance

Two medicines in one question?

Interactions

7.1Antacids

7.2Uricosuric Drugs

7.3Drug Interference with Laboratory Tests

Pregnancy and breastfeeding

8.1Pregnancy Risk Summary

Adverse reactions

Composition

Strengths and forms

Official product information